Horses have been known to stop eating when they are sick or otherwise distressed. If your horse has stopped eating, the first thing you should do is check your horse’s vital signs, heart rate, respiration, and temperature. If the either temperature, pulse, or respiration is elevated, your horse may be showing signs of physical stress, and you should contact your veterinarian immediately. If all of the vital signs are normal, in all likelihood you do not have an immediate emergency. However, you should continue to monitor your horse over the next 24 hours to be sure it is not developing an illness that will require attention. For reference, a mature horse’s normal temperature range is 99 to 101.5 degrees; normal respiration ranges from 8 to 16 breaths per minute, and the normal resting heart rate or pulse ranges from 28 to 52 beats per minute. Do not hesitate to call your veterinarian if one or more of these vital signs is elevated. Sometimes a horse will go off feed if its teeth are too long and causing a sore mouth. If you suspect this is the case, have your veterinarian check your horse’s teeth. Finally, sometimes hot, humid weather will cause a horse to slow its feed intake, but this will usually not stop the horse from eating altogether.